Is Training for a Marathon Good for my Mental Health?

I am at Week 10 of my training plan for the 2025 London Marathon. My first marathon.

I know running is good for my mental health, but this is when I aimlessly go for a run on a beautiful day and run until I feel like it – not when I have a busy schedule of increasingly longer runs and progressively more tiring weeks of intense physical activity, all while the deadline is approaching of an enormous effort that I may never finish.

So yes, I am stressed about it. And what do I do to cope with stress? I study the topic, as an academic question. And this piece is the results of my studies.

Having spent countless hours reading blogs, scrolling through runners’ social media accounts, listening to podcasts, and talking with marathoner friends, in this piece, I have summarised the things that I have learned about training for a marathon that are endorsed by so many sources that they must be true. This knowledge is keeping my stress at manageable levels and it is protecting my mental health. I hope it can help other fellow runners training for the London Marathon or any other in the next few months.

I am broadly following the TCS Improver Training Plan by the organisers of the London Marathon. In my usual grandiosity, I have chosen the plan for “runners who may have already completed a marathon and are looking to improve on a previous performance” – despite the fact I’ve never run one. Surely running five half-marathons is just the same, right?

Unsurprisingly, you do need to run a lot to train for a marathon. What I’ve come to realise is that it’s not just about running long distances. You need to be training at a variety of speeds, both below and above your target speed for the race.

Surprisingly, the most difficult part of the training is running slower than you think, in the so called “Heart Zone 2”. Zone 2 is the easy-level running in which you are able to have a conversation or sing your favourite song aloud, albeit with some effort. For me, it would be a recent Italian trashy song, a so called “tormentone”.

Running in Zone 2, the theory goes, improves muscles’ ability of creating energy by increasing the amount of blood vessels and of mitochondria - the cellular organs responsible for energy production - in the muscles. Indeed, a recent analysis of scientific literature in this field confirms this. Above Zone 2 (in “Zone 3”), you start producing lactic acid, which is the breakdown product when blood sugar is used to give energy to the muscles.

Your easy runs should be long – really long and getting longer. Last Sunday mine was 25.6km, in two weeks it will be 29km. The longest will be 30-32km, and you should never run for longer than this until you are in the race. The crowd will lift you and carry you for the last 10-12 km of the marathon, even if you have never run it before – or so everybody says.

However, because it’s so slow, this training alone will not allow you to run at a fast pace on the day of the marathon, it will only help you to run for a long period of time. So, you also need “interval training” - you run fast (reaching the top 10-20% of your maximum heart rate) for a few minutes, then recover with jogging, then repeat. This high-speed interval training will allow you to improve your speed and performance on the day of the race.

The problem is, running is not enough. Everybody says that you must do physical exercise other than running, and I really agree. Weightlifting, cross-training, anaerobic exercise, biking, find what you like and get your legs strong and your core tight, to prevent injuries and reduce fatigability.

As I discussed in ITM before, I am a Kung Fu martial artist and as such I have a routine of 2 hours of Tai Chi and 4 hours of Kung Fu per week, plus a whole-day training camp every 3-4 months. In addition, I do 2 hours of cross-fit. When I decided to train for the marathon, I also decided that my routine would not change – because it is really important for my mental health. So, I added my running to this routine.

I started out thinking that marathon training was going to help me lose weight. Not so. You need to eat a lot, especially before, during and after the long runs. Before the long run you should have a big breakfast 2 hours before beginning, or a small one 30-45 minutes before, plus 30-60 mg of carbohydrates (sugar) per hour of running. This is the equivalent of 2-3 bananas or 75-150 raisins per hour! And then you need a second breakfast, within one hour of finishing the run, or half an hour if you are a woman, with both carbohydrates and proteins, for repairing muscle stress and replenish energy storage.

Of course, most of the carbohydrates during the long runs will not come from food but will come from sport gels. There are so many and there are many reviews online, but, basically, try as many types/brands as possible when you train, so that you know which one you like and will work on the day of the marathon.

Also, do not forget to drink water and sport/electrolyte drinks, before, during and after a run. Drink a lot, like, really a lot, especially if it is hot outside. Dehydration is a serious, life-threatening problem, especially during long runs, and hydration before you start is crucial: unless your urine is clear or a very pale yellow, don’t go on a long run. Talk about anxiety-provoking knowledge.

It's important to remember that after a run you must force yourself to eat and drink, even if you will not be feeling hungry or thirsty. The run activates our body stress response, and this will shut down our sensations of hunger and thirst as it prioritises our “flight or fight” response. So, tell your body that there are no lions in the room and that instead you need to eat and drink.

Alcohol: you are not supposed to drink it during training, but I am ignoring this. Well, I have decreased it but not stopped it. I think this is also helping with my stress levels. Drinking less, I mean.

One thing that is certainly helping my mental health since I began training is to sleep more. I made only one new year’s resolution coming into 2025 which was to improve my sleeping habits.

Professional runners sleep 12 hours a day when they train – 10 hours at night plus a nap of 2 hours. While admittedly most of us cannot do this, I have been trying to maximise my healthy level of sleep. I’ve started organising dinners with friends earlier than usual, and when at home I force myself to stop watching TV. One suggestion I heard, and really liked, is that you should not wake up early just to run. Sleep it’s such a priority that you must shuffle your engagements and find another time of the day to run, but must not sacrifice your sleep.

Is this knowledge helping me?

There is a risk that so many online recommendations and opinions activate the obsessive academic in me, so at some point I had to stop reading and focussing on what I knew – and I have summarised here.

Remember, there is only one way to enjoy the marathon : train, train, train. The harder you train, the easier the race day will be.

Or so I am hoping and praying.

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I am running the marathon to support the Psychiatry Research Trust, a charity that promotes research and education in mental health (please support me here).